E13
Mysa Load Type / Compatibility Error

Thermostat displays E13 and cannot control a 2-wire in-floor heating system correctly.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Incorrect load type selected in Mysa settings, Incompatible low-voltage or electronic load connected, Internal load-type detection circuit fault

How to Fix / Troubleshooting

Safety first: Turn OFF power at the breaker before changing any wiring or load connections.

Steps to resolve:

  • Confirm heater type: Verify that the connected system is a compatible line-voltage resistive load (e.g., electric baseboard or in-floor heating) and not a low-voltage or fan-forced system that Mysa does not support.
  • Check settings: In the Mysa app or on the thermostat, go to Settings > Device > Load Type (or similar) and ensure the correct heater type is selected.
  • Inspect wiring: Confirm that only the heater load is connected to the LOAD terminals and that no control transformers or relays are incorrectly wired.

If the load is compatible and settings are correct but E13 persists, the internal load-type detection circuitry may be faulty. Replace the thermostat.

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Repair Difficulty

Medium 3/5

Required Part

Main Control Board (Load-Type Detection Circuit)
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